Receive the latest national-international updates in your inbox

Shortly after smoke began filling an MBTA Orange Line train on Wednesday, passengers began fleeing. Many were trapped because the doors would not open. necn Investigates Jason Frazer explains why some couldn't get out and what the MBTA is doing about it. (Published Friday, Nov. 4, 2016)

Passengers were evacuated from a smoky MBTA train, some climbing out windows, in Boston's Back Bay during the Wednesday afternoon commute.

The train's doors did not open as smoke filled Back Bay Station, though the MBTA said its doors were not supposed to open. The train's motorman opened doors manually, while passengers evacuated themselves or with assistance from authorities.

MBTA spokesperson Joe Pesaturo initially told necn the train's motor overheated. The agency later said in a statement that the cause has yet to be determined, but that it was "most likely related to the motor."

A video taken by Twitter user @cloudfrye and shared with necn shows responders rushing people off the Orange Line train.

The user, identified as Claudia, says passengers were calm until police arrived.

"Basically everyone was calm and there was a ton of smoke outside the train and then a police officer starts hammering the window WITHOUT WARNING and then walks away and another police officer enters and screams for everyone to calm down," she wrote to necn. "Of course, everyone starts panicking and he opens the door and we get off the train."

According to the MBTA, "some passengers began to self evacuate and were assisted by transit officers and the motor person" around 4:41 p.m. The agency said the fact that the doors did not open was not the result of a technical issue.

"Doors on the subway remained closed because the train had moved away from the platform. Doors did not malfunction. The motor person had begun promptly opening doors to allow passengers to evacuate safely, away from the live third rail," the MBTA wrote in a statement.

Boston fire crews evacuated the train station at 4:57 p.m., according to the MBTA. Service on the Orange Line's southbound side resumed at 5:41 p.m. and service the northbound side resumed at 6:15 p.m.

This isn’t the first time trains along the Orange Line have had trouble. In February, passengers were forced to flee after a strip of metal from the side of a train car fell onto the tracks near State Street and sparked a fire. The MBTA then inspected all 120 of its Orange Line cars and determined 13 of them needed to be repaired in order to prevent future issues.